The invention relates to various labeling machines and printing machines of the general type which include article feed rolls. The feed roll apparatus is particularly useful with respect to automatic article labeling or printing machines. There are a large number of machines in which a plurality of articles such as envelopes are processed (e.g., envelopes being supplied in a stack and requiring correct feeding, one by one) in a line position for printing or labeling. Many machines utilizing automatic feed arrangements do not permit continuous loading while the machine is in operation and/or cannot accommodate various sized or shaped articles.
Labeling and printing machines capable of automatically handling individual articles such as envelopes, magazines, newspapers and the like are available which can handle these various shaped and sized articles without changing the structural configuration of the machines. However, in order to accommodate the variety of shapes and sizes, the machine must be structured to enable resetting of the components of the machines, particularly the feed apparatus. That is, the machine must be structured to allow adjustment of the spacing between the feed rollers from a thickness of two or three sheets of paper to magazine or newspaper thicknesses. In these circumstances, the roller feed apparatus and printing apparatus is raised or lowered in accordance with the material being processed.
Prior art machines have normally utilized mechanical, threaded drive means for adjusting the raising and lowering of the rollers resulting in a quite tedious and time consuming mechanism. In these prior machines, various worm wheels and worm in shaft systems are married in order to allow for hand knob manual adjustment wheels. The rotation of these adjustment shafts, worms and gears move the moveable portion of otherwise stationary feed rollers and printing heads upwardly and downwardly depending on the articles being printed or labeled. Major adjustments in some prior machines are made by manual nuts which raise and lower a portion of the working roller in order to accommodate various thicknesses of material which are intended to be processed in the apparatus.
Thus, the article feed mechanisms employed in known methods and machines provide adjustment capabilities to the operator for adjusting the separation of the upper and lower feed rollers, i.e., adjustment of the roller nip. Usually, this adjustment is made by a threaded mechanism which must be adjusted by turning the knob multiple rounds in order to enlarge the nip to receive thicker documents or articles. The feed rollers are in a vertical relationship and when two or more roller nips are created through multiple roller pairs, equal nip pressure on the articles is achieved only by trial and error manipulations by the operator of individual threaded adjustment means. Whether or not the operator creates equal pressure for contact with the media being processed depends on adjustment of one roller nip at a time followed by an assessment as to whether the pressure is the same with each roller. Such adjustments are very tedious and time consuming.
In one known system, a single adjustment knob is utilized for achieving total height adjustment for the articles to be processed. This single height adjustment is also used for fine tuning. Other systems allow for one set of rollers (either bottom or upper rollers) to be cam shaped in order to provide clearance for variable thickness articles and to achieve a gripping action without hopping. However, such apparatus still presents complexities of adjustment. For example, in one such product, upper feed rollers are cammed up and down by a lifter mechanism but each roller must be tediously set individually to finely adjust the rollers to exert identical pressure against the media. The same adjustment knob also controls the roller height for changes in media thickness. In another apparatus, the lower feed rollers are cammed up and down and are tied together with the upper rollers but must again be adjusted by a knob mechanism for media thickness. In all of these prior art feed roller mechanisms adjustments of height or roller nip is accomplished by tedious twist knob, screw adjustments.